The present invention concerns an interdental tooth-brush of improved structure.
As known, interdental tooth-brushes are at present widely spread on the market and they generally consist of a suitably shaped support bar, at the free end of which there is mounted a small replaceable brush stick.
Since, for evident reasons of oral hygiene as well as for practical reasons, said small brush stick should be appropriately thrown away quite often and replaced by a new one, it is important for it to be mounted on and removed from the shaped support bar in a very simple and quick way.
For this purpose, it is known to construct the brush stick in the form of a thin braided wire, from which radially project a plurality of single bristles, generally of synthetic material. Said braided wire stick thus comprises a main portion, carrying the bristles for the required cleaning operations, and a tail portion with no bristles, by which it is applied onto the shaped support bar. The brush stick is applied by inserting its tail portion into a transversal hole at the end of the support bar, folding it along said bar and locking it thereon by suitable means.
In a known construction--for example according to U.S. Pat. No. 4,319,377 and U.S. Pat. No. 4,222,143--said locking means consist of an annular bush, by which said tail portion is fixed into an axial retention slot formed at the end of the support bar. The drawback of such locking means lies however in the fact that the bush may slip out of the support bar--for instance when removing the brush stick--and get lost.
The European Patent Publication No. 311,937 provides for a slidable locking bush, which cannot slip off and get lost because of the presence of stop pins. Nevertheless, in this case, the brush stick is mounted by way of a block incorporating the tail portion of the braided wire, whereby the locking bush does not have to bend said braided wire.
According to another known solution, the locking is obtained by means of a half-bush, hinged onto the support bar and covering laterally said folded tail portion of the brush stick. This system prevents the locking means from accidentally slipping out; nevertheless, the half-bush is not apt to ensure a very reliable retention and, furthermore, it comprises sharp edges which can cause trouble to the user when cleaning his or her teeth.